1. Field of the Invention
The invention relates to a flying shear system, more particularly to an adaptive cut-length flying shear system having provisions to regulate the length of bloom tail scrap.
2. Description of the Related Art
The process flow diagram of a conventional flying shear system with static cut-length control is shown in FIG. 1. A programmer, through the aid of statistical data and computer programs, can calculate the required weight of bloom from primary bloom information, such as the unit weight per meter of the bloom and the programmed length of bloom. And by using primary billet requirements, such as the unit weight per meter of the product billet and the allowable range of product billet length, the programmer can then calculate the required cutting length. This information is then passed on to an operator, who, after considering other factors, such as metal composition and the billet temperature before cutting, decides the actual cutting length.
Referring once more to FIG. 1, a bloom 10 is fed to a rolling means 12 to produce a finish rolled billet 14 with a reduced cross section. The operator manually operates a cut-length control circuit 18, which in turn controls a flying shear means 16. The output of the flying shear means 16 is a plurality of product billets 141 with head and tail scraps 142.
The disadvantages of using the above described "flying shear system with static cut-length control" are as follows:
1. The conventional flying shear system uses the unit weight per meter of the bloom, and the programmed length of bloom to determine the required weight of bloom. However, the cross section of cast blooms tends to gradually increase because of wearing of the casting molds. The actual length and cross-section of the cast blooms is therefore different from the programmed length and cross-section, and the calculated required weight of bloom is different from the actual required weight of bloom. This is a defect which the conventional flying shear system cannot correct.
2. The conventional flying shear system uses the required weight of bloom, the unit weight per meter of the product billet, and the allowable range of product billet length to determine the required cutting length. However, the cross section of finish rolled billets tends to gradually increase because of wearing of the compression rollers. The actual weight per meter of the product billet is therefore different from the initial weight per meter of the product billet, and the calculated required cutting length is thus also inaccurate.
3. The conventional flying shear system is complicated and requires experienced personnel to properly operate the system.
4. The cut-length control circuit 18 is manually operated. It is thus impractical to compute a required accurate cutting length for each individual finish rolled billet.
5. Tail scrap length produced by the conventional flying shear system ranges from 0 cm to 60 cm. Tail scraps longer than 20 cm means loss of product, while tail scraps shorter than 5 cm can cause operational troubles.